FIELD OF THE INVENTION
The invention relates to a microelectronic component of sandwich construction, a method for producing it, and an inverter that includes the microelectronic component.
Such inverters can be used to convert direct current into alternating current, and are needed particularly for controlling motors. Power modules, of the kind used so far in inverters, as a rule include a substrate, on which a number of power chips as well as components for triggering, evaluating, protecting, and the like are disposed side by side. The substrate, for example, can be a filled plastic film, which is disposed on an aluminum base plate. A conductor track system, typically made of copper, is located on the plastic film. The connection among the individual components and between them and the conductor tracks is effected by so-called thick wire bonding. In so-called econopacks, bonding is not done to the conductor tracks but rather directly to terminal pins. Both in econopacks and in standard modules, terminal pins are needed for bonding, and they are complicated and expensive to make because they must be manufactured in a special production step with special tools.
Because all the system components are disposed side by side in the same plane, the known power modules are relatively large, and the connection paths spanned by bond wires are relatively long. In such an arrangement, a very poor power-inductance layout is obtained, and complicated technology is required. To prevent dynamic countercoupling, one additional control source is needed for the control terminal. Wire bonding is also a weak point in terms of alternating load stresses, which impairs the reliability of the power modules.
German Patent Application DE 34 06 528 A1 teaches the fixation of components when components are being soldered to conductor tracks. After soldering, the components should remain bonded to the conductor tracks as firmly as possible. To compensate for any possible mechanical stresses, compensation pieces made of molybdenum can optionally be provided.
U.S. Pat. No. 4,922,376 discloses the use of spring elements with components for contacting the components in a way that enables repair of a failed contact. If a contact fails, it can be repaired by loosening a screw connection and replacing the applicable spring element.
U.S. Pat. No. 5,203,075 discloses a method for connecting a first, flexible conductor track substrate to a second conductor track substrate. The first substrate has conductive balls, that are soldered to soldering points on the second substrate.
U.S. Pat. No. 4,855,867 discloses a flexible conductor track substrate onto which semiconductor chips are mounted that are electrically conductively connected by balls to a fixed circuit board.